Skip to content
Closed
Changes from 1 commit
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Prev Previous commit
Next Next commit
long line
  • Loading branch information
riccardobrasca committed Oct 5, 2025
commit 69e1d86852cae7a13359ae6a6edae8a4d1e0ec10
3 changes: 2 additions & 1 deletion Mathlib/RingTheory/RootsOfUnity/CyclotomicUnits.lean
Original file line number Diff line number Diff line change
Expand Up @@ -79,7 +79,8 @@ theorem geom_sum_isUnit' (hζ : IsPrimitiveRoot ζ n) (hj : j.Coprime n) (hj_Uni
| 1 => simp_all
| n + 2 => exact geom_sum_isUnit hζ (by linarith) hj

/-- The explicit formula for the unit whose existence is the content of `associated_pow_sub_one_pow_of_coprime`. -/
/-- The explicit formula for the unit whose existence is the content of
`associated_pow_sub_one_pow_of_coprime`. -/
theorem pow_sub_one_mul_geom_sum_eq_pow_sub_one_mul_geom_sum (hζ : IsPrimitiveRoot ζ n)
(hn : 2 ≤ n) : (ζ ^ j - 1) * ∑ k ∈ range i, ζ ^ k = (ζ ^ i - 1) * ∑ k ∈ range j, ζ ^ k := by
apply mul_left_injective₀ (hζ.sub_one_ne_zero (by omega))
Expand Down